I have follow your guide to this page https://www.revenuecat.com/docs/tools/paywalls/displaying-paywalls
And implement the code in my view, but the paywall is not showing up, what am I missing?
```
.presentPaywallIfNeeded(
requiredEntitlementIdentifier: "pro",
purchaseCompleted: { customerInfo in
print("Purchase completed: \(customerInfo.entitlements)")
},
restoreCompleted: { customerInfo in
// Paywall will be dismissed automatically if "pro" is now active.
print("Purchases restored: \(customerInfo.entitlements)")
}
)
```